1. Field of the Invention
The present invention relates to a hinge assembly for rotationally attaching a first member to a second member to allow rotational movement of the first member relative to the second member between a closed position and an open position.
2. Description of the Prior Art
Hinge assemblies for rotationally attaching a first member to a second member to allow rotational movement of the first member relative to the second member between a closed position and an open position are known in the prior art. In particular spring loaded hinge assemblies that assist the opening of the first member relative to the second member by storing energy in a spring during the closing operation are shown in U.S. Pat. No. 7,055,215 B1 to Ligtenberg at al., issued on Jun. 6, 2006. However, these hinges require special machined springs that are extremely costly and complex to manufacture. The multi-layer torsion bar of the present invention, which functions to assist the opening of the first member relative to the second member by storing energy during the closing operation, drastically reduces the cost and complexity of spring manufacture while maintaining the same performance. These and other advantages of the present invention will become apparent from the description and drawings that follow. None of the prior art hinge assemblies are seen to teach or suggest the unique features of the present invention or to achieve the advantages of the present invention.